Filament tensioning apparatus



July l2, 1966 o. N. SMITH ETAL FILAMENT TENSIONING APPARATUS 2 Sheets-Sheet 1 Filed Jan. 24, 1964 INVENTOR o/1/E Men/73N ff/774,

July 12, 1966 o. N. SMITH ETAL FILAMENT TENSIONING APPARATUS Filed Jan. 24, 1964 2 Sheets-Sheet 2 United States Patent O FILAMENT TENSIONING APPARATUS Oliver Newton Smith, Kinston, and Leigh ONeill Vanneman, Sr., Griffon, N.C., assignors to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Jan. 24, 1964, Ser. No. 339,999 3 Claims. (Cl. 242-153) 'Ihis invention relates to means for handling high denier yarn at substantially uniform tension filament-toiilament and more particularly to means for avoiding loss of individual filament tension control during passage of the yarn transfer knots required for tying-in fresh packages of yarn in a continuous operation.

Manufacture of yarns having very high total denier and comprising a large number of filaments is frequently accomplished by the plying of several yarn ends into a single yarn. Unless substantially every filament is tensioned to the same degree in such an operation, the differential stresses developed end-to-endin the plied yarn Will result in buckling of individual ends leading to unacceptable non-uniformities in the form of filament loops in the final, plied structure. Also, in some instances, it is desirable to interlace the filaments according to the process disclosed by Bunting et a'l. in U.S. Patent 2,985,995, dated May 30, 1961. The desired mechanism for controlling interlace of high filament count yarns is to have all filaments of equal tension so that the interlacing forces can act on all filaments uniformly. If a large difference in filament tension exists from the outside to the inside of a filament bundle, an applied radial and/or axial interlacing force will form loops in the low tension filaments while interlacing the bulk of the bundle. lf the tension is too low, all filaments will be loopy; and, conversely, if the tension is excessive (for correction of loopy condition), the bundle will have low interlace or none at all.

Ordinary yarn tensioners have not been found adequate for the handling of high denier yarns since the restraining force applied to filaments which are in direct contact with the snubbing surfaces at any moment is usually greater than that which can be applied at that moment to the filaments which are not directly in contact with the snubbing surfaces. If the yarn is to be interlaced, this leads to unacceptable filament loops as the yarn passes through the interlacing jet. When wound on a package Without interlacing, non-uniform filamentto-filament tension will lead to non-uniform fabrics as the variable stresses decay after unwinding. In addition, When a transfer knot passes through an ordinary tensioner, it will cause the snubbing surfaces to move apart suddenly (bounce), resulting in complete loss of tension regulation until the tensioner loading is restored to normal. Moreover, if the tendency to bounce is suppressed by damping the tensioner action, the passage of a transfer knot results in a brief but very large increase in tension.

An object of this invention is to provide means for the precise controlling of tension in high denier yarns. A further object is to provide tensioning means which are essentially unaffected by passage of transfer knots. A still further object is to provide means for uniformly tensioning high denier yarns for interlacing to a unitary, loop-free structure. Other objects will appear hereinafter.

The objects of this invention are accomplished by a filament tensioner comprising a pair of substantially identical assemblies, each consisting of a base member on which are mounted at least one and preferably a plurality of slotted projecting elements. In operation,

3,260,473 Patented July 12, 1966 ICC one assembly (upper) is placed in spacedsuperimposed relationship with respect to the other assembly, such that the projecting elements of each are alternately intermeshed, the slots of the respective projecting elements being thus aligned with respect to each other to form an orifice to accommodate high denier yarn and providing a substantially straight yarn path. The yarn is tensioned by the weight of the upper assembly, which in turn is vertically movable, so that the shape of the orifice is capable of being correspondingly varied to accommodate a transfer knot passing through the filament tensioner, With the tension still being applied b-y the Weight of the upper assembly.

In the drawings, which illustrate the invention and apparatus discussed hereinafter:

FIGURE 1 is a perspective view of the preferred embodiment of the filament tensioner;

FIGURE 2 is a cross-sectional view taken along line 2 2 of FIGURE 1;

FIGURE 3 is a partial top plan view of the filament tensioner;

FIGURE 4 is a cross-sectional View taken along line 4 4 of FIGURE 2;

FIGURE 5 is Ia detail view of a projecting element;

FIGURE 6 is a bottom plan view of the projecting element of FIGURE 5; and FIGURE 7 is an exploded perspective view of the filament tensioner.

Referring to FIGURE 1, the preferred embodiment of the filament tensioner of this invention comprises a pair of substantially identical base members 10 and 12 which are positioned in a spaced superimposed relationship, with upper base member 10 being vertically movable. The base members each have a plurality of oppositely extending projecting elements 14 and 16 which are attached (as shown) by suitable fasteners to the respective base members and are positioned iny an alternately intermeshed relationship. Each projecting element has a substantially vertical elongated slot 18 with the length of the slot being such that adjacent projecting elements form an orifice to accommodate the introduction of the variable diameter yarn 20.

FIGURES 2 and 3 show more fully the intermeshing relationship of projecting elements 14 and 16 and the path of yarn 20 -as it passes through the filament tensioner. FIGURE 4 illustrates the orifice formed by adjacent projecting elements 14 and 16 to accommodate the heavy denier yarn 20. FIGURES 5 and 6 show 1n detail the preferred embodiment of a projecting element with the edges and base of slot 18 being rounded to prevent contact of the heavy denier yarn with sharp edges. FIGURE 7 shows in exploded perspectivethe relationships of the elements of the filament tensioner shown in FIGURE 1.

To assemble for operation, yarn 20 is laid in slots 18 of projecting elements 16 of base member 12 from which base member 10 has been removed. Base member 10 is then placed in spaced superimposed relationship with base member 12 as described in FIGURE 1.

The tension on yarn 20 is such that the Weight of base member 10` is carried by the yarn. The impact of a transfer knot7 lifts base member 10 slightly above its normal equilibrium position first at the entrance end, momentarily at both ends as the knot passes the centrally-located projecting member and finally at the exit end as the knot energes from the filament tensioner. At no time during passages of the transfer knot does the filament tensioner tend to bounce or lose yarn compression.

Adjustment of the tension level can be accomplished by changing var-ions relationships in the base member such as adjustment of the Weight, choice of materials and adjustment of the thickness or addition or removal of supplemental weights. Alternatively, some of the projecting members may be removed, resulting in a reduction in snubbing area as well as in weight.

The present invention provides a more uniform control of tensions than was heretofore possible in handling high denier yarns having transfer knots. When used as a tensioner to precede as interlaoing jet, the principal advantage of the use of the filament tensioner of this invention is a dramatic reduction in frequency of filament loops in the final product (interlaced plied yarn). This is an indication that the regulation of the individual filament tension is superior to that achievable with prior art tensioners. When used in a packaging operation, the filament tensioner offers substantial improvement in the uniformity of the yarn package and in the quality of products made therefrom. Since weaving, knitting, tire-cord manufacture and other textile operations are sensitively dependent on tension uniformity of the filaments, it is important that the yarn be supplied from packages in Whichzitbis uniformly stressed. Otherwise, the subsequent decay of stresses in the textile structure will leave objectionable non-uniformities. It is of particular advantage that transfer knots may be employed without any detrimental eflect on quality resulting from the loss of tension control encountered during the passage of transfer knots through the filament tensioner.

The filament tensioner of this invention constrains the high denier yarn bundle in a variable orifice that is smoothly actuated by the filament bundle which may be variable in compacted size due to, for example, variable denier, non-uniform orientation of filaments or transfer knots, This constraint imparts a more uniform tension flament-to-filament and permits operation at a lower level of tension, resulting in a uniform product.

Since many different embodiments of the invention may be made without depar-ting from the spirit and scope thereof, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the appended claims.

What is claimed is:

1. A filament tensioner capable of exerting constant tension on yarn of variable diameter comprising an upper and lower base member positioned in spaced superimposed relationship, said upper base member being vertically movable and having a plurality of downwardly extending projecting elements, said lower base member having a plurality of upwardly extending projecting elements which alternately intermesh with said downwardly extending projecting elements, said projecting elements each having substantially vertical elongated slots arranged in register to form an orifice for said yarn, with said orifice becoming elongated in cross-section when said upper base member recedes from said lower base member, said upper base member being adapted to exert tension by gravity upon said yarn passing through said orifice, whereby upon receipt of a relatively large diameter portion of said yarn, said orifice assumes said elongated cross-section to -accommodate said large diameter portion and said upper base member retains said tension by gravity on said yarn.

2. The filament tensioner of claim 1 wherein said projecting elements of said base members are detachable.

3. The filament tensioner of claim 1 wherein the walls of said projecting elements defining said elongated slots are rounded, centrally located in said projecting elements, and are open at the outward extremities of said projecting elements.

References Cited by the Examiner UNITED STATES PATENTS 1,564,995 12/1925v Allen 242-149 1,756,649 4/1930 Madden et al. 242-153 1,833,588 11/1931 Pierce 242-154 2,451,889 10/1948 Toone 242-149 2,900,144 8/1959 Maier 242-153 2,974,897 3/1961 Carroll 242-154 MERVIN STEIN, Primary Examiner.

STANLEY N. GILREATH, Examiner.

W. S. BURDEN, Assistant Examiner. 

1. A FILAMENT TENSIONER CAPABLE OF EXERTING CONSTANT TENSION ON YARN OF VARIABLE DIAMETER COMPRISING AN UPPER AND LOWER BASE MEMBER POSITIONED IN SPACED SUPERIMPOSED RELATIONSHIP, SAID UPPER BASE MEMBER BEING VERTICALLY MOVABLE AND HAVING A PLURALITY OF DOWNWARDLY EXTENDING PROJECTING ELEMENTS, SAID LOWER BASE MEMBER HAVING A PLURALITY OF UPWARDLY EXTENDING PROJECTING ELEMENTS WHICH ALTERNATELY INTERMESH WITH SAID DOWNWARDLY EXTENDING PROJECTING ELEMENTS, SAID PROJECTING ELEMENTS EACH HAVING SUBSTANTIALLY VERTICAL ELONGATED SLOTS ARRANGED IN REGISTER TO FORM AN ORIFICE FOR SAID YARN, WITH SAID ORIFICE BECOMING ELONGATED IN CROSS-SECTION WHEN SAID UPPER BASE MEMBER RECEDES FROM SAID LOWER BASE MEMBER, SAID UPPER BASE MEMBER BEING ADAPTED TO EXERT TENSION BY GRAVITY UPON SAID YARN PASSING THROUGH SAID ORIFICE, WHEREBY UPON RECEIPT OF A RELATIVELY LARGE DIAMETER PORTION OF SAID YARN, SAID ORIFICE ASSUMES SAID ELONGATED CROSS-SECTION TO ACCOMMODATE SAID LARGE DIAMETER PORTION AND SAID UPPER BASE MEMBER RETAINS SAID TENSION BY GRAVITY ON SAID YARN. 